The National Ready Mixed Concrete Association (NRMCA) sends out a press release touting their recent political victory in Washington State, and their new promotional campaign, “Build with Strength.” Hilarity ensues.
There is a lot of wood in Washington State. Meanwhile, the state faces some serious challenges, including building new housing, addressing climate change and dealing with rural poverty. That’s one of the reasons the State legislature recently considered legislation to promote the use of Cross Laminated Timber (CLT), the plywood-on-steroids building system that can replace concrete in low and mid-rise buildings. It’s relatively new technology in the USA, but it makes a lot of sense in the west, because the wood sequesters carbon, CLT buildings go up really quickly, it doesn’t burn very well and it puts people to work.
Of course, it’s all about protecting the children and, the poor (who else lives in multifamily?) and the old people.
But the real hilarity ensues when Kevin Lawlor of Build With Strength, their new publicity campaign, gets going. He writes:
As Washington and the entire Pacific Northwest enter wildfire season, the onus is on those with the means to make a difference to ensure Washington State’s buildings are constructed with strong and resilient materials.
At least five percent of the CO2 produced each year comes from the making of cement. That's chemistry; heat up limestone to make cement and it gives off CO2. And it is CO2 that drives climate change that is likely contributing to the wildfires that are consuming the Pacific Northwest’s forests.
But wood absorbs CO2 as it grows. That's biology. When one makes CLT from trees, it sequesters CO2 for the life of the building. CLT doesn’t burn very well, and it certainly doesn’t rot or promote mold if protected with a roof and a wall over it, much like every concrete building. It is also extremely strong, and compared to concrete, extremely resilient.
The Readymix people also don’t mention the footprint of the aggregate that gets hauled to their plants, or the deaths caused by readymix trucks racing to get to construction sites before the mix hardens. Because concrete is heavy it takes a lot more trucks to build a building out of concrete than it does out of light flat panels of CLT, all of which are pushing out CO2 and particulates and PAHs that are killing the children and old people that the industry is trying so hard to protect.
The NRMCA is touting the big virtue of concrete, that it’s strong. But they also distort the truth, showing buildings like the Willis Tower as models of strength, when like almost every other office building in Chicago or New York it is built out of steel. The Willis is one of the world's most identifiable and important steel towers!) They say it doesn’t deteriorate, rot or yield, yet where I live they have had to replace almost every balcony and parking garage in the city because it did exactly that. They show pictures of Rome and say concrete lasts forever, without mentioning that Roman concrete does not have cement made by heating limestone, and does not have steel reinforcement. In other words, it is not the same stuff they are peddling.
Finally, they go on about how concrete buildings are resistant to the forces of nature, without mentioning earthquakes, where wood is considered the “most suitable material for earthquake resistant construction due to its light weight and shear strength across the grains.” or the billions that have been spent fixing reinforced concrete buildings and the failures of flat slab and shear wall or column and slab buildings. As one study notes, “Unfortunately, earthquake experience has proved that this form of construction is vulnerable to failure in which the thin concrete slab fractures around the supporting columns and drops downward, leading potentially to a complete progressive collapse of a building as one floor cascades down onto the floors below.”
There are many types of structures where there is no substitute for concrete. But where there is, such as in low and mid-rise buildings, architects, builders and regulators have to do everything they can to promote low carbon alternatives to concrete. That’s not picking winners and losers; that’s ultimately choosing between life and death.